How does a mercury barometer work?

A mercury barometer balances the weight of mercury in a glass tube against the atmospheric pressure above a reservoir of mercury at its base to provide a measurement of atmospheric pressure. This weather instrument works like a set of scales to forecast the weather. read more

While an array of barometer types exist, two main types are used in meteorology: the mercury barometer and the aneroid barometer. How the Classic Mercury Barometer Works The classic mercury barometer is designed as a glass tube about 3 feet high with one end open and the other end sealed. read more

The two traditional kinds of barometer are called Torricellian and aneroid (dial) barometers—and here's how they work. Torricellian barometers. Photo: A Torricellian barometer (sometimes called a mercury barometer) is an inverted (upside-down) glass tube standing in a bath of mercury. read more